The market for prostitution

In this age of epidemic, “multiple partnerships save lives” (Steven Landsburg). How? Because it eliminates the market for prostitution, which is a venue for the spread of the epidemic.

Let’s imagine a community where women are required to sleep only with their husbands. But husbands are more likely to sleep with women other than their wives. The monogamous policy, however, prevents them from sleeping with the wives of other men. Hence, there emerges a prostitution market, which supplies more sex and satisfies the demand for more partners in a monogamous community.

For simplicity’s sake, let’s say the population of this community is 100. There are 50 men and 50 women. There are only 10 singles (5 males, 5 females), the rest are married. Let’s say monogamy is preached more strictly on wives, and culture has made a policy exemption on husbands due to their sexual instincts. Let us assume that the natural propensity of husbands to sleep with another woman is 1 extra partner per year. Given the number of single men, the number of husbands is 45. The number of wives is also 45. But if each husband, based on natural necessity, sleeps with 1 extra partner per year, and they’re not allowed to sleep with the wives of other husbands, they will resort to the 5 single females. Since there is very few and precious supply of extra sex, a market for prostitution arises because of the bargaining power of the single females. Assuming these 5 all engage in prostitution, they will have to meet the demand of 45 husbands and will need to sleep with multiple partners throughout the year. If all husbands must be satisfied, the average number of each prostitute’s customer is 9 husbands a year.

Now let’s say one husband (1% of the population) is HIV positive. He infects one prostitute, who in turn infects 8 more men. The 9 infected husbands will infect their 9 wives. If each husband tries the other prostitutes, then the other husbands and wives are also infected.

Now if we allow the 45 wives to have multiple partners and throw monogamy out of the equation, the husbands can sleep with other wives. Hence the total number of females in the population that are potential sexual partners becomes 50. If there are 50 women that can supply the demand of 45 husbands, then the bargaining power of females in providing sex is reduced, and hence no prostitution market will form, and no venue for the rapid spread of the epidemic.